diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index cc00e2c4ac..a8fad9a276 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -177,6 +177,7 @@ OBJS-$(CONFIG_BOXBLUR_FILTER)                += vf_boxblur.o boxblur.o
 OBJS-$(CONFIG_BOXBLUR_OPENCL_FILTER)         += vf_avgblur_opencl.o opencl.o \
                                                 opencl/avgblur.o boxblur.o
 OBJS-$(CONFIG_BWDIF_FILTER)                  += vf_bwdif.o yadif_common.o
+OBJS-$(CONFIG_CAS_FILTER)                    += vf_cas.o
 OBJS-$(CONFIG_CHROMABER_VULKAN_FILTER)       += vf_chromaber_vulkan.o vulkan.o
 OBJS-$(CONFIG_CHROMAHOLD_FILTER)             += vf_chromakey.o
 OBJS-$(CONFIG_CHROMAKEY_FILTER)              += vf_chromakey.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 01a7a8bf9f..f094baf496 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -168,6 +168,7 @@ extern AVFilter ff_vf_bm3d;
 extern AVFilter ff_vf_boxblur;
 extern AVFilter ff_vf_boxblur_opencl;
 extern AVFilter ff_vf_bwdif;
+extern AVFilter ff_vf_cas;
 extern AVFilter ff_vf_chromahold;
 extern AVFilter ff_vf_chromakey;
 extern AVFilter ff_vf_chromashift;
diff --git a/libavfilter/vf_cas.c b/libavfilter/vf_cas.c
new file mode 100644
index 0000000000..b7e1879f4b
--- /dev/null
+++ b/libavfilter/vf_cas.c
@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2020 Paul B Mahol
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/imgutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct CASContext {
+    const AVClass *class;
+
+    float strength;
+    int planes;
+    int nb_planes;
+
+    int depth;
+    int planeheight[4];
+    int planewidth[4];
+
+    AVFrame *in;
+
+    int (*do_slice)(AVFilterContext *s, void *arg,
+                    int jobnr, int nb_jobs);
+} CASContext;
+
+static inline float lerpf(float v0, float v1, float f)
+{
+    return v0 + (v1 - v0) * f;
+}
+
+static int cas_slice8(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
+{
+    CASContext *s = avctx->priv;
+    const float strength = -lerpf(9.f, 4.1f, s->strength);
+    AVFrame *out = arg;
+    AVFrame *in = s->in;
+
+    for (int p = 0; p < s->nb_planes; p++) {
+        const int slice_start = (s->planeheight[p] * jobnr) / nb_jobs;
+        const int slice_end = (s->planeheight[p] * (jobnr+1)) / nb_jobs;
+        const int linesize = out->linesize[p];
+        const int in_linesize = in->linesize[p];
+        const int w = s->planewidth[p];
+        const int w1 = w - 1;;
+        const int h = s->planeheight[p];
+        const int h1 = h - 1;
+        uint8_t *dst = out->data[p] + slice_start * linesize;
+        const uint8_t *src = in->data[p];
+
+        if (!((1 << p) & s->planes)) {
+            av_image_copy_plane(dst, linesize, src + slice_start * linesize, in_linesize,
+                                w, slice_end - slice_start);
+            continue;
+        }
+
+        for (int y = slice_start; y < slice_end; y++) {
+            for (int x = 0; x < w; x++) {
+                int mn, mn2, mx, mx2;
+                int a = src[FFMAX(y - 1, 0) * in_linesize + FFMAX(x - 1, 0)];
+                int b = src[FFMAX(y - 1, 0) * in_linesize + x];
+                int c = src[FFMAX(y - 1, 0) * in_linesize + FFMIN(x + 1, w1)];
+                int d = src[y * in_linesize + FFMAX(x - 1, 0)];
+                int e = src[y * in_linesize + x];
+                int f = src[y * in_linesize + FFMIN(x + 1, w1)];
+                int g = src[FFMIN(y + 1, h1) * in_linesize + FFMAX(x - 1, 0)];
+                int h = src[FFMIN(y + 1, h1) * in_linesize + x];
+                int i = src[FFMIN(y + 1, h1) * in_linesize + FFMIN(x + 1, w1)];
+                float amp, weight;
+
+                mn  = FFMIN3(FFMIN3( d, e, f), b, h);
+                mn2 = FFMIN3(FFMIN3(mn, a, c), g, i);
+
+                mn = mn + mn2;
+
+                mx  = FFMAX3(FFMAX3( d, e, f), b, h);
+                mx2 = FFMAX3(FFMAX3(mx, a, c), g, i);
+
+                mx = mx + mx2;
+
+                amp = sqrtf(av_clipf(FFMIN(mn, 511 - mx) / (float)mx, 0.f, 1.f));
+
+                weight = amp / strength;
+
+                dst[x] = av_clip_uint8(((b + d + f + h) * weight + e) / (1.f + 4.f * weight));
+            }
+            dst += linesize;
+        }
+    }
+
+    return 0;
+}
+
+static int cas_slice16(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
+{
+    CASContext *s = avctx->priv;
+    AVFrame *frame = arg;
+
+    for (int p = 0; p < s->nb_planes; p++) {
+        const int slice_start = (s->planeheight[p] * jobnr) / nb_jobs;
+        const int slice_end = (s->planeheight[p] * (jobnr+1)) / nb_jobs;
+        const int linesize = frame->linesize[p];
+        uint8_t *dst = frame->data[p] + slice_start * linesize;
+        for (int y = slice_start; y < slice_end; y++) {
+            for (int x = 0; x < s->planewidth[p]; x++) {
+            }
+            dst += linesize;
+        }
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    CASContext *s = ctx->priv;
+    AVFrame *out;
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
+        return AVERROR(ENOMEM);
+    }
+    av_frame_copy_props(out, in);
+
+    s->in = in;
+    ctx->internal->execute(ctx, s->do_slice, out, NULL,
+                           FFMIN(in->height, ff_filter_get_nb_threads(ctx)));
+    av_frame_free(&in);
+    s->in = NULL;
+
+    return ff_filter_frame(ctx->outputs[0], out);
+}
+
+static av_cold int query_formats(AVFilterContext *avctx)
+{
+    static const enum AVPixelFormat pixel_fmts[] = {
+        AV_PIX_FMT_GRAY8,
+        AV_PIX_FMT_GRAY9,
+        AV_PIX_FMT_GRAY10,
+        AV_PIX_FMT_GRAY12,
+        AV_PIX_FMT_GRAY14,
+        AV_PIX_FMT_GRAY16,
+        AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
+        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
+        AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
+        AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
+        AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_YUVJ411P,
+        AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
+        AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
+        AV_PIX_FMT_YUV440P10,
+        AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
+        AV_PIX_FMT_YUV440P12,
+        AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
+        AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
+        AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
+        AV_PIX_FMT_YUVA420P,  AV_PIX_FMT_YUVA422P,   AV_PIX_FMT_YUVA444P,
+        AV_PIX_FMT_YUVA444P9, AV_PIX_FMT_YUVA444P10, AV_PIX_FMT_YUVA444P12, AV_PIX_FMT_YUVA444P16,
+        AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA422P16,
+        AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA420P16,
+        AV_PIX_FMT_GBRAP,     AV_PIX_FMT_GBRAP10,    AV_PIX_FMT_GBRAP12,    AV_PIX_FMT_GBRAP16,
+        AV_PIX_FMT_NONE
+    };
+
+    AVFilterFormats *formats = NULL;
+
+    formats = ff_make_format_list(pixel_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+
+    return ff_set_common_formats(avctx, formats);
+}
+
+static av_cold int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *avctx = inlink->dst;
+    CASContext *s = avctx->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+
+    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+    s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
+    s->planewidth[0]  = s->planewidth[3]  = inlink->w;
+
+    s->depth = desc->comp[0].depth;
+    s->nb_planes = desc->nb_components;
+    s->do_slice = s->depth <= 8 ? cas_slice8 : cas_slice16;
+
+    return 0;
+}
+
+static const AVFilterPad cas_inputs[] = {
+    {
+        .name           = "default",
+        .type           = AVMEDIA_TYPE_VIDEO,
+        .filter_frame   = filter_frame,
+        .config_props   = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad cas_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+#define OFFSET(x) offsetof(CASContext, x)
+#define VF AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
+
+static const AVOption cas_options[] = {
+    { "strength", "set the sharpening strength", OFFSET(strength), AV_OPT_TYPE_FLOAT, {.dbl=0}, 0, 2215,  VF },
+    { "planes",  "set what planes to filter",    OFFSET(planes),   AV_OPT_TYPE_FLAGS, {.i64=7}, 0, 15, VF },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(cas);
+
+AVFilter ff_vf_cas = {
+    .name          = "cas",
+    .description   = NULL_IF_CONFIG_SMALL("Contrast Adaptive Sharpen."),
+    .priv_size     = sizeof(CASContext),
+    .priv_class    = &cas_class,
+    .query_formats = query_formats,
+    .inputs        = cas_inputs,
+    .outputs       = cas_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+    .process_command = ff_filter_process_command,
+};
